Effect of hydrogen on hot deformation behaviors of TiAl alloys

The effect of hydrogen on hot deformation behaviors of Ti–47Al alloys was studied using a hot simulator. The optimized deformation temperature for Ti–47Al alloys was 1150 °C. Flow stress and peak stress were reduced with increasing addition of hydrogen. Peak stress can be reduced by about 33.3% with 1% hydrogen addition at 1150 °C and strain rate of 1 × 10−2 s−1. There were less dislocation tangles and more twinning and stacking faults in the hydrogenated alloys compared with the unhydrogenated alloys. The hydrogen-induced decrease of flow stress was attributed to hydrogen-induced dislocation mobility and hydrogen-promoted dynamic recrystallization and twinning.